During surgical procedures a suction wand is employed to remove blood from the wound so as to improve visibility to the surgeon and to collect recovered blood for return to the patient. Recovered blood is treated, as by defoaming, filtering and use of a centrifuge to separate damaged blood cells from blood that is to be returned to the patient. The defoaming and filtering apparatus is generally a housing of relatively large internal volume, about 4.2 liters, with part of the housing forming a storage reservoir for the defoamed and filtered blood. To remove blood from the storage reservoir, a separate pump, such as a costly peristaltic pump is employed. Blood is drawn into the filter by applying vacuum to the housing interior. The large filter housing volume acts as a large fluidic capacitance that significantly slows system response to changes in the applied vacuum.
Recovery of blood involves use of mechanical devices which inherently inflict damage on the blood cells because of mechanical handling during the blood recovery. Conventionally recovered blood is cleaned by a centrifuge device, commonly called a cell-saver, to separate intact red blood cells from the lower molecular weight, damaged red cell components as well as other less desirable formed elements of blood.
Various types of blood recovery systems have been employed in the past, generally embodying a suction wand employing a vacuum to suck blood from the wound site through the tip of the wand, which is positioned in the wound site. However, it is well known that all such presently available blood recovery systems cause substantial mechanical blood cell damage, resulting in smaller amounts of recovered blood of relatively lower quality available to be returned to the patient.
Accordingly, it is an object of the present invention to provide blood transport and blood recovery systems that minimize or avoid above mentioned problems.